Digitally addressable electronic devices are generally connected to a bus system in parallel and include gate means which respond to an address in form of a specific bit pattern which is transmitted via address lines included in said bus. In such a system it is necessary to individually set the gate means included in such an addressable device to a specific address. In a system, which includes a plurality of different, addressable devices which may be repeatedly exchanged, this kind of addressing is cumbersome and may lead to trouble which is caused by errors in setting the gate means. Such trouble may become very serious when the digitally addressable electronic devices are medical apparatusses used for monitoring body functions of seriously sick persons so that a failure in monitoring may have lethal consequences.